& Joannie Dobbs Saturday, February 9, 2008
Brown rice can provide vital magnesium
Evidence is mounting that diets low in magnesium contribute to several chronic diseases. The average adult in the U.S. consumes only 75 to 80 percent of recommended intake for this essential mineral. Moderately low magnesium intake has no obvious immediate symptoms. Over time, however, low magnesium intake likely contributes to many chronic ailments.
Question: What health problems are related to low magnesium consumption?
Answer: The most common conditions linked to chronically low magnesium intake include high blood pressure, cardiovascular disease, diabetes and osteoporosis. Low intake of magnesium might even play a role in the so-called metabolic syndrome that is characterized by high waist circumference, a poor blood lipid pattern, high blood pressure and high blood glucose.
Q: Why do so many people have low magnesium intake?
A: As a nation, we tend to eat too many refined, "empty calorie" types of foods. This can reduce the intake of many vitamins and minerals, including magnesium.
Q: How much magnesium is recommended?
A: For adults over 30 years of age, 320 milligrams per day are recommended for women, and 420 mg for men. The recommendation for younger adults and teenagers is slightly less.
Q: What are the best sources of magnesium?
A: A cup of cooked spinach provides about 150 mg of magnesium. Other minerals like calcium and iron are poorly absorbed from spinach, but magnesium is efficiently absorbed.
An ounce of most nuts and seeds contributes 50 to 75 mg of magnesium, and cooked beans have 70 to 100 mg per cup. Cooked brown rice has about 80 mg per cup compared with refined white rice's 25 mg. Similarly, a slice of white bread has only about 7 mg compared with more than 20 in whole wheat bread.
Milk products can be a significant source of magnesium with about 45 mg in a cup of yogurt and 25 mg in a cup of milk. Overall, a diet with a wide variety of unprocessed wholesome foods can easily meet magnesium needs.
Q: Can you get too much magnesium?
A: It is easy to get too much magnesium from supplements or medicines but highly unlikely to consume excessive amounts strictly from foods. For this reason, the Institute of Medicine established a tolerable upper intake level for magnesium that is specifically related to supplements and medications. Its upper limit of 350 mg per day from supplements or medications is based on the fact that too much magnesium taken at one time can cause diarrhea.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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